Field of the Invention
The invention relates to methods and apparatuses for delivering additives to reacting materials. More particularly, it relates to methods and apparatuses for enabling operations wherein reaction-modifying additives can be substituted and/or combined quickly, easily, and in a customizable fashion.
Background of the Invention
In many commercial production facilities today, additive feed systems are permanently hard-piped to a mixing and/or reaction site, such as a reaction vessel. This enables the selected additive, or mixture of additives, to be fed into the site at a desired time in the operation cycle to ultimately produce a desired product. Such products may include, in non-limiting example, polymerized products such as polyethylenes, polyurethanes, and polypropylenes; non-polymerized products; and the like. In these and in similar applications, a single additive, such as, for example, a catalyst, co-catalyst, scavenger, other reaction- or product-modifying additive, or combination thereof, is typically offloaded into storage tanks, combined batchwise to a smaller “day” or “run” tank, and then the material from each run tank is metered and fed to a metering pump, from whence it is introduced into a reactor with reactant materials or added to a post-reactor site for product modification
Unfortunately, the above-described arrangement has certain drawbacks. One is that, when the additive has been exhausted, production must usually be shut down in order to replenish the run tank.
Another drawback is that it is relatively difficult to switch to a different additive in order to produce a different product. This is because, again, the overall production operation must first be shut down, the input line must be flushed in some way to prevent cross-contamination, and the production (with or without different reactant materials) must then be reinitiated. In some instances, it may be necessary to waste large proportions of tanks of additives where only a small amount is needed for a production run. Alternatively, a whole new production line may be needed, which is very expensive.
A third drawback is that it is also difficult or impossible to customize, or experiment to customize, a variety of additives. This includes customization as to types, combination of types, and/or concentrations thereof. In particular, it is difficult to customize such “on the fly,” i.e., during operation, meaning without shutting down the production line as a whole and installing temporary tubing of some type.
In view of the above, it would be desirable to be able to reduce or eliminate some or all of the drawbacks mentioned hereinabove.